Method of fabricating diaphragm assemblies



April 18, 1967 W. LIBEN METHOD OF FABRICATING DIAPHRAGM ASSEMBLIES Filed Dec. 9, 1963 MFA c E INVENTOR MLL/AM L BE N ATTORNEY United States Patent 3,314,866 METHOD OF FABRICATING DIAPHRAGM ASSEMBLIES William Liben, 11404 Monticello Ave, Silver Spring, Md. 20902 Fiied Dec. 9, 1963, Ser. No. 329,102 6 Claims. (Cl. 204-31) similar applications. A main object of the invention is to provide a novel and improved the type having a very thin metal vibratory diaphragm element, said method providing a diaphragm element of Further objects and advantages become apparent from the following description and claims, and from the accompanying drawings, wherein:

Y constructed by a method according to the present invention.

FIGURE 2 is a vertical cross-sectional view taken method of the present invention.

FIGURE 3 is a vertical cross-sectional view taken through a matrix member employed in forming a diaphragm assembly by the method of the present invention.

during the diaphragm fabrication step of the method of the present invention.

FIGURE 6 is a vertical cross-sectional view taken through the clamped members and showing the diaphragm elements electroplated thereon.

FIGURE 7 is an elevational view, partly in vertical cross-section, showing how the matrix member is slid ed the diaphragm assembly in the final stage of the fabrication method of the present invention.

Electromechanical transducers are used to convert a mechanical motion into an electrical signal. Two examples of such transducers are shown in FIGURES 1 and 2. In FIGURE 1, the transducer is designated generally at 11 and comprises a frame 12 in which is supported a U-shapecl magnetic core 13 provided with a pickup winding 14. Designated at 15 is a diaphragm assembly comprising a rigid supporting ring-shaped frame 16 carrying a vibratory diaphragm element 17 disposed adjacent the ends of the poles 48, 18 of core 13. Vibratory motion of the diaphragm element 17 produces changes in the reluctance of the magnetic circuit associated with the coil 14, whereby correspondingelectrical signals are induced in the coil. The signals are related to the motion of the diaphragm, and therefore to the cause of said 3,3143% Patented Apr. 18, 1967 motion, such as changes in the acting on the diaphragm.

In FIGURE 2, the transducer is designated generally at 11 and comprises a rigid main frame 12' in which is secured a rigid first condenser plate 19 and a transgas or liquid pressure duce changes in capacity between the plate 19 and the diaphragm assembly 15, which provides a useful signal related to the motion of the diaphragm element.

It is often desirable to make the vibratory diaphragm element 17 very thin. With methods of fabrication employed in the past, the requirement for a very thin diaphragm element has created difiicu'lt problems in the fabrication and handling shaped frame 16 in a manner to produce an integrated structure combining the support ring and the diaphragm element. A typical procedure according to the present the same metal as the intended vibratory diaphragm eleof the metal to be deposited, the clamped assembly 20, 16 constituting the cathode. The clamped assembly and anode are conmatrix 20 is slid ring 16, as illustrated in FIGURE 7.

ofr" the support The remaining ring 16 and the While a specific embodiment of an improved method of fabricating a metal diaphragm assembly has been disclosed in the foregoing description, it will be understood that various modifications within the spirit of the invention may occur to those skilled in the art. Therefore it is intended that no limitations be placed on the invention except as defined by the scope of the appended claims.

What is claimed is:

1. A method of fabricating a diaphragm assembly comprising forming a passivated surface on a matrix plate, detaehably securing a rigid metal frame ring to said matrix plate in contact with said passivated surface, electroplating a film of the same metal as said ring adherently onto the inside of the ring and across the central aperture of the ring, and then removing the matrix plate.

2. A method of fabricating a diaphragm assembly comprising forming an oxidized surface on a matrix plate on which plating is non-adherent, detachably securing a rigid metal frame ring to said matriv plate in contact with said oxidized surface, electroplating a film of the same metal as said ring adherently onto the inside of the ring and across the central aperture of the ring adjacent said oxidized surface, and then removing the matrix plate.

3. A method of fabricating a diaphragm assembly comprising forming an oxidized surface on a matrix plate on which platitng is non-adherent, detacha'bly securing a rigid metal frame ring to said matrix plate in contact with said oxidized surface, placing the matrix plate and frame ring in an electroplating bath, electroplating a film of the same metal as said ring adherently onto the inside of the ring and across the central aperture of the ring adjacent said oxidized surface, removing the matrix plate, frame ring and plated film from the electroplating bath, and then detaching the matrix plate.

4. A method of fabricating a diaphragm assembly comprising forming an oxide coating on a fiat surface of a matrix plate on which plating is non-adherent, detachably clamping a rigid metal frame ring to said matrix plate in contact with said oxide coatng, electroplatng a film of the same metal as said ring adherently onto the inside of the ring and across the central aperture of the ring adjacent said oxide coating, unclamping the matrix plate relative to the frame ring, and then sliding the matrix plate off the frame ring.

5. A method of fabricating a diaphragm assembly comprising forming an oxide coating on a flat surface of a matrix plate on which plating is non-adherent, detachably clamping a rigid metal frame ring to said matrix plate in contact with said oxide coating, placing the matrix plate and frame ring in an electroplating bath, electroplating a film of the same metal as said ring adherently onto the inside of the ring and across the central aperture of the ring adjacent said oxide coating, removing the matrix plate, frame ring and plated film from the electroplating bath, and then detaching the matrix plate.

6. A method of fabricating a diaphragm assembly comprising forming an oxide coating on a flat surface of a stainless steel matrix plate on which plating is non-adherent, detacha bly clamping a rigid metal frame ring to said matrix plate in contact with said oxide coating, placing the matrix plate and frame ring in an electroplating bath, electroplating a film of the same metal as said ring adherently onto the inside of the ring and across the central aperture of the ring, said film being adjacent the oxide coating in the area bounded by said central aperture, removing the matrix plate, frame ring and plated film from the plating bath, unclamping the matrix plate, and then sliding the matrix plate off the frame ring and plated film.

No references cited.

HOWARD S WILLIAMS, Primary Examiner. D. R. VALENTINE, Assistant Examiner. 

3. A METHOD OF FABRICATING A DIAPHRAGM ASSEMBLY COMPRISING FORMING AN OXIDIZED SURFACE ON A MATRIX PLATE ON WHICH PLATITING IS NON-ADHERENT, DETACHABLY SECURING A RIGID METAL FRAME RING TO SAID MATRIX PLATE IN CONTACT WITH SAID OXIDIZED SURFACE, PLACING THE MATRIX PLATE AND FRAME RING IN AN ELECTROPLATING BATH, ELECTROPLATING A FILM OF THE SAME METAL AS SAID RING ADHERENTLY ONTO THE INSIDE OF THE RING AND ACROSS THE CENTRAL APERTURE OF THE RING ADJACENT SAID OXIDIZED SURFACE, REMOVING THE MATRIX PLATE, FRAME RING AND PLATED FILM FROM THE ELECTROPLATING BATH, AND THEN DETACHING THE MATRIX PLATE. 